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- #include <stdio.h>
- #include <time.h>
- #include <library.h>
- typedef bool (*attackfn_t)(void *subj, u_char *data, size_t len);
- static void start_timing(struct timespec *start)
- {
- clock_gettime(CLOCK_PROCESS_CPUTIME_ID, start);
- }
- static uint64_t end_timing(struct timespec *start)
- {
- struct timespec end;
- clock_gettime(CLOCK_THREAD_CPUTIME_ID, &end);
- return (end.tv_nsec - start->tv_nsec) +
- (end.tv_sec - start->tv_sec) * 1000000000;
- }
- static int intcmp(const void *a, const void *b)
- {
- return *(uint64_t*)a - *(uint64_t*)b;
- }
- static uint64_t median(uint64_t *m, int count)
- {
- qsort(m, count, sizeof(uint64_t), intcmp);
- return m[count / 2];
- }
- static bool timeattack(attackfn_t attackfn, void *subj, size_t dlen,
- u_int iterations, u_int distance)
- {
- struct timespec start;
- u_char test[dlen];
- uint64_t mini, maxi, t[256], m[256][10];
- float fastdist = 0, slowdist = 0;
- int i, j, k, l, byte, limit, retry = 0;
- int fastest = 0, slowest = 0;
- memset(test, 0, dlen);
- /* do some iterations to fill caches */
- for (i = 0; i < iterations; i++)
- {
- attackfn(subj, test, dlen);
- }
- for (byte = 0; byte < dlen;)
- {
- memset(t, 0, sizeof(t));
- memset(m, 0, sizeof(m));
- limit = iterations * (retry + 1);
- /* measure timing for all patterns in next byte */
- for (k = 0; k < 10; k++)
- {
- for (j = 0; j < 256; j++)
- {
- for (l = 0; l < 100; l++)
- {
- test[byte] = j;
- start_timing(&start);
- for (i = 0; i < limit; i++)
- {
- attackfn(subj, test, dlen);
- }
- m[j][k] += end_timing(&start);
- }
- }
- }
- for (j = 0; j < 256; j++)
- {
- t[j] = median(m[j], countof(m[j]));
- }
- /* find fastest/slowest runs */
- mini = ~0;
- maxi = 0;
- for (j = 0; j < 256; j++)
- {
- if (t[j] < mini)
- {
- mini = min(t[j], mini);
- fastest = j;
- }
- if (t[j] > maxi)
- {
- maxi = max(t[j], maxi);
- slowest = j;
- }
- }
- /* calculate distance to next result */
- mini = ~0;
- maxi = 0;
- for (j = 0; j < 256; j++)
- {
- if (fastest != j && t[j] < mini)
- {
- mini = min(t[j], mini);
- fastdist = (float)(t[j] - t[fastest]) / distance;
- }
- if (slowest != j && t[j] > maxi)
- {
- maxi = max(t[j], maxi);
- slowdist = (float)(t[slowest] - t[j]) / distance;
- }
- }
- if (fastdist > 1.0f)
- {
- fprintf(stderr, "byte %02d: %02x (fastest, dist %02.2f)\n",
- byte, fastest, fastdist);
- test[byte] = fastest;
- retry = 0;
- byte++;
- }
- else if (slowdist > 1.0f)
- {
- fprintf(stderr, "byte %02d: %02x (slowest, dist %02.2f)\n",
- byte, slowest, slowdist);
- test[byte] = slowest;
- retry = 0;
- byte++;
- }
- else
- {
- if (retry++ > 5 && byte > 0)
- {
- fprintf(stderr, "distance fastest %02.2f (%02x), "
- "slowest %02.2f (%02x), stepping back\n",
- fastdist, fastest, slowdist, slowest);
- test[byte--] = 0;
- }
- else if (retry < 10)
- {
- fprintf(stderr, "distance fastest %02.2f (%02x), "
- "slowest %02.2f (%02x), retrying (%d)\n",
- fastdist, fastest, slowdist, slowest, retry);
- }
- else
- {
- printf("attack failed, giving up\n");
- return FALSE;
- }
- }
- }
- if (attackfn(subj, test, dlen))
- {
- printf("attack successful with %b\n", test, dlen);
- return TRUE;
- }
- printf("attack failed with %b\n", test, dlen);
- return FALSE;
- }
- CALLBACK(attack_memeq1, bool,
- u_char *subj, u_char *data, size_t len)
- {
- return memeq(data, subj, len);
- }
- CALLBACK(attack_memeq2, bool,
- u_char *subj, u_char *data, size_t len)
- {
- return memeq(subj, data, len);
- }
- CALLBACK(attack_memeq3, bool,
- u_char *subj, u_char *data, size_t len)
- {
- int i;
- for (i = 0; i < len; i++)
- {
- if (subj[i] != data[i])
- {
- return FALSE;
- }
- }
- return TRUE;
- }
- CALLBACK(attack_memeq4, bool,
- u_char *subj, u_char *data, size_t len)
- {
- int i, m = 0;
- for (i = 0; i < len; i++)
- {
- m |= subj[i] != data[i];
- }
- return !m;
- }
- CALLBACK(attack_memeq5, bool,
- u_char *subj, u_char *data, size_t len)
- {
- return memeq_const(subj, data, len);
- }
- static bool attack_memeq(char *name, u_int iterations, u_int distance)
- {
- struct {
- char *name;
- attackfn_t fn;
- } attacks[] = {
- { "memeq1", attack_memeq1 },
- { "memeq2", attack_memeq2 },
- { "memeq3", attack_memeq3 },
- { "memeq4", attack_memeq4 },
- { "memeq5", attack_memeq5 },
- };
- u_char exp[16];
- int i;
- srandom(time(NULL));
- for (i = 0; i < sizeof(exp); i++)
- {
- exp[i] = random();
- }
- fprintf(stderr, "attacking %b\n", exp, sizeof(exp));
- for (i = 0; i < countof(attacks); i++)
- {
- if (streq(name, attacks[i].name))
- {
- return timeattack(attacks[i].fn, exp, sizeof(exp),
- iterations, distance);
- }
- }
- return FALSE;
- }
- CALLBACK(attack_chunk1, bool,
- u_char *subj, u_char *data, size_t len)
- {
- return chunk_equals(chunk_create(subj, len), chunk_create(data, len));
- }
- CALLBACK(attack_chunk2, bool,
- u_char *subj, u_char *data, size_t len)
- {
- return chunk_equals_const(chunk_create(subj, len), chunk_create(data, len));
- }
- static bool attack_chunk(char *name, u_int iterations, u_int distance)
- {
- struct {
- char *name;
- attackfn_t fn;
- } attacks[] = {
- { "chunk1", attack_chunk1 },
- { "chunk2", attack_chunk2 },
- };
- u_char exp[16];
- int i;
- srandom(time(NULL));
- for (i = 0; i < sizeof(exp); i++)
- {
- exp[i] = random();
- }
- fprintf(stderr, "attacking %b\n", exp, sizeof(exp));
- for (i = 0; i < countof(attacks); i++)
- {
- if (streq(name, attacks[i].name))
- {
- return timeattack(attacks[i].fn, exp, sizeof(exp),
- iterations, distance);
- }
- }
- return FALSE;
- }
- CALLBACK(attack_aead, bool,
- aead_t *aead, u_char *data, size_t len)
- {
- u_char iv[aead->get_iv_size(aead)];
- memset(iv, 0, sizeof(iv));
- return aead->decrypt(aead, chunk_create(data, len), chunk_empty,
- chunk_from_thing(iv), NULL);
- }
- static bool attack_aeads(encryption_algorithm_t alg, size_t key_size,
- u_int iterations, u_int distance)
- {
- u_char buf[64];
- aead_t *aead;
- bool res;
- aead = lib->crypto->create_aead(lib->crypto, alg, key_size, 0);
- if (!aead)
- {
- fprintf(stderr, "creating AEAD %N failed\n",
- encryption_algorithm_names, alg);
- return FALSE;
- }
- memset(buf, 0xe3, sizeof(buf));
- if (!aead->set_key(aead, chunk_create(buf, aead->get_key_size(aead))))
- {
- aead->destroy(aead);
- return FALSE;
- }
- memset(buf, 0, aead->get_iv_size(aead));
- if (!aead->encrypt(aead, chunk_create(buf, 0), chunk_empty,
- chunk_create(buf, aead->get_iv_size(aead)), NULL))
- {
- aead->destroy(aead);
- return FALSE;
- }
- fprintf(stderr, "attacking %b\n", buf, aead->get_icv_size(aead));
- res = timeattack(attack_aead, aead, aead->get_icv_size(aead),
- iterations, distance);
- aead->destroy(aead);
- return res;
- }
- CALLBACK(attack_signer, bool,
- signer_t *signer, u_char *data, size_t len)
- {
- return signer->verify_signature(signer, chunk_empty, chunk_create(data, len));
- }
- static bool attack_signers(integrity_algorithm_t alg,
- u_int iterations, u_int distance)
- {
- u_char buf[64];
- signer_t *signer;
- bool res;
- signer = lib->crypto->create_signer(lib->crypto, alg);
- if (!signer)
- {
- fprintf(stderr, "creating signer %N failed\n",
- integrity_algorithm_names, alg);
- return FALSE;
- }
- memset(buf, 0xe3, sizeof(buf));
- if (!signer->set_key(signer, chunk_create(buf, signer->get_key_size(signer))))
- {
- signer->destroy(signer);
- return FALSE;
- }
- if (!signer->get_signature(signer, chunk_empty, buf))
- {
- signer->destroy(signer);
- return FALSE;
- }
- fprintf(stderr, "attacking %b\n", buf, signer->get_block_size(signer));
- res = timeattack(attack_signer, signer, signer->get_block_size(signer),
- iterations, distance);
- signer->destroy(signer);
- return res;
- }
- static bool attack_transform(char *name, u_int iterations, u_int distance)
- {
- const proposal_token_t *token;
- token = lib->proposal->get_token(lib->proposal, name);
- if (!token)
- {
- fprintf(stderr, "algorithm '%s' unknown\n", name);
- return FALSE;
- }
- switch (token->type)
- {
- case ENCRYPTION_ALGORITHM:
- if (encryption_algorithm_is_aead(token->algorithm))
- {
- return attack_aeads(token->algorithm, token->keysize / 8,
- iterations, distance);
- }
- fprintf(stderr, "can't attack a crypter\n");
- return FALSE;
- case INTEGRITY_ALGORITHM:
- return attack_signers(token->algorithm, iterations, distance);
- default:
- fprintf(stderr, "can't attack a %N\n", transform_type_names, token->type);
- return FALSE;
- }
- }
- int main(int argc, char *argv[])
- {
- library_init(NULL, "timeattack");
- atexit(library_deinit);
- lib->plugins->load(lib->plugins, getenv("PLUGINS") ?: PLUGINS);
- if (argc < 3)
- {
- fprintf(stderr, "usage: %s <attack> <iterations> <distance>\n", argv[0]);
- fprintf(stderr, " <attack>: memeq[1-5] / chunk[1-2] / aead / signer\n");
- fprintf(stderr, " <iterations>: number of invocations * 1000\n");
- fprintf(stderr, " <distance>: time difference in ns for a hit\n");
- fprintf(stderr, " example: %s memeq1 100 500\n", argv[0]);
- fprintf(stderr, " example: %s aes128gcm16 100 4000\n", argv[0]);
- return 1;
- }
- if (strpfx(argv[1], "memeq"))
- {
- return !attack_memeq(argv[1], atoi(argv[2]), atoi(argv[3]));
- }
- if (strpfx(argv[1], "chunk"))
- {
- return !attack_chunk(argv[1], atoi(argv[2]), atoi(argv[3]));
- }
- return !attack_transform(argv[1], atoi(argv[2]), atoi(argv[3]));
- }
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